No. 2 seed Gustavo Kuerten also loses in the first round. Serena Williams begins her title defense with a win.

Two-time champion Patrick Rafter lost in five sets Tuesday night to the inspired and uncanny brilliance of Galo Blanco, a Spaniard who had lost in the first round of every other Grand Slam event this year.

With several thousand wildly cheering fans still in Arthur Ashe Stadium, Blanco rallied back from a minibreak in the final tiebreaker, winning five of the last six points, to beat Rafter 7-6 (7-3), 2-6, 6-3, 1-6, 7-6 (7-5). The 3-hour, 2-minute match ended at 12:07 a.m.

Rafter, runner-up to Pete Sampras at Wimbledon, came into the U.S. Open unseeded because he had been out most of the year while recovering from shoulder surgery.

But the 27-year-old Australian, the U.S. Open champion in 1997 and 1998, was considered the most dangerous floater in the men's draw, a player who was nearly as much of a favorite to win the title as Sampras or Andre Agassi.

Blanco, a 23-year-old ranked No. 114, had lost in the first round of 13 of his 16 Grand Slam tournaments since 1996. His best performance in a major came at the 1997 French Open, where he reached the quarterfinals before losing to Rafter in straight sets in their only other meeting.

"That was my most important match in my life," Blanco said. "So I beat him here in this tournament, and he beat me there in my tournament. That's life."

Rafter drilled 24 aces past Blanco and kept charging the net, but Blanco stood his ground on the baseline and pummeled Rafter with passing shots.

Blanco's particular splendor on a cool, breezy night was his ability to limit his unforced errors, committing only two in the first set and 38 overall. The more aggressive Rafter made 52.

Blanco aced Rafter 17 times, seven in the final set.

It was the second big upset on the second day of the tournament. Australian qualifier Wayne Arthurs' 26 aces helped bring him to a 4-6, 6-3, 7-6 (7-4), 7-6 (7-1) victory over French Open champion and No. 2 seed Gustavo Kuerten.

There were no such upset in the women's draw.

Serena Williams arrived in defense of her title resplendent in tie-dyed lilac and black, and flashing a smile that bespoke the confidence of a champion.

Williams ripped a return winner on the first point as she proceeded to crush 19-year-old Slovenian Tina Pisnik 6-3, 6-2.

Williams showed that her foot -- which caused her to default from her last match nine days ago -- no longer bothered her. She repeatedly ran down what looked to be winners and kept the ball in play.

Williams had four aces and 24 winners against 22 unforced errors. Pisnik had 19 unforced errors and six winners.

Like Williams, Lindsay Davenport had no problem in her opening match, crushing Gala Leon Garcia of Spain 6-0, 6-1.

Davenport, seeded second, began her bid to regain the title she won in 1998 by crushing Gala Leon Garcia of Spain. Davenport needed 18 minutes to take the first set and 44 minutes to complete the 6-0, 6-1 victory.

"I was happy to get it over with quickly," said Davenport, who has advanced to the second round in 25 of the past 26 Grand Slam events.

Arthurs knocked off No. 12 Alex Corretja in the first round of last year's U.S. Open. Against Kuerten, Arthurs used serves that reached speeds of 133 mph to fire 25 aces.

"His serve was too strong for me," said Kuerten, who converted only one of nine break points. "If he plays anybody in the draw he has a chance to win. He's a very tough opponent."

After a solitary break by each player in the first two sets, Arthurs and Kuerten held serve the rest of the way and let the tiebreakers decide matters. In those, Arthurs proved dominant, and he ended the affair with an ace up the middle.

The left-hander's powerful serve was made even tougher by the hard surfaces at the U.S. National Tennis Center.

"I've always liked the courts here," he said. "I hope they never slow them down."

Kuerten, who reached the quarterfinals last year, becomes the first No. 2 seed to lose in the first round since Goran Ivanisevic was eliminated in 1994. Ivanisevic, three times a runner-up at Wimbledon, lost 3-6, 6-0, 6-1, 6-0.

The hard-serving Ivanisevic, who may have played his last U.S. Open match, was booed when he finished his match on an outside court.

"I'm undecided to play anymore this year," said Ivanisevic, who has been bothered by a sore shoulder that may need surgery. "It's tough to say yes; it's tough to say no. It's not fun anymore. My head is a little confused. The battery is empty."